--- title: "How to Sterilise Jam Jars (UK & US) | Jelly Glimmer" description: "How to sterilise jam jars: the UK oven method and the USDA boiling method side by side, when canners can skip it, a jar counter and printable gift labels." url: https://jellyglimmer.me/sterilising-jam-jars/ --- The British oven method and the USDA boiling method # How to sterilise jam jars In Britain, jam jars are usually washed in hot soapy water, rinsed and dried in a 140 °C oven (120 °C fan, gas 1), then filled hot with hot jam, as BBC Food and BBC Good Food describe. The USDA method is different: boil the empty jars for 10 minutes, plus 1 minute for every 1,000 ft of altitude, whenever the filled jars will be processed for less than 10 minutes in a boiling-water canner; for 10 minutes or longer, clean hot jars are enough. Count your jars and lids below, and print gift labels. ## UK and US methods, side by side The two methods belong to two different ways of making jam, so follow one or the other from start to finish rather than mixing their steps. ### UK Oven method, open pan 1. Wash the jars and lids in hot, soapy water and rinse them well. 2. Dry them on a baking tray in an oven at 140 °C (120 °C fan, gas 1, about 275 °F): BBC Good Food says around 10 minutes until dry, BBC Food’s technique page says 20 minutes. 3. Take rubber seals off and boil them for 2 to 3 minutes instead: dry heat damages them. 4. Time it so the jars are still hot when the jam is ready; BBC Good Food starts them about 20 minutes before. 5. Fill the hot jars with hot jam and seal straight away. ### US Boiling method, USDA 1. Wash the jars in hot water with detergent and rinse, or wash them in a dishwasher. This cleans but does not sterilise them. 2. If the jam will be processed less than 10 minutes, stand the empty jars upright on the canner rack and cover with hot water by 1 inch. 3. Boil 10 minutes below 1,000 ft, plus 1 minute for each additional 1,000 ft. 4. Lift out and drain one jar at a time, and keep the hot water for processing. 5. Fill, add lids prepared as the maker says, and process for the tested time. The Food Standards Agency doesn’t publish a jar-sterilising method for home jam, so the British column follows the BBC’s widely used cookery guidance. The US column is the USDA *Complete Guide to Home Canning* method, published by the National Center for Home Food Preservation (NCHFP). Two methods, two systems: dry oven heat for British open-pan jam; boiling water for jam that will be processed in a canner. ## Do you need to sterilize jars for canning? Only when the processing time is short. NCHFP: “All jams, jellies, and pickled products processed less than 10 minutes should be filled into sterile empty jars.” Most jams and jellies are processed 5 minutes at sea level, so their jars are sterilised. Jars for foods processed 10 minutes or longer, such as the tested chutneys or apple butter in quarts, don’t need it: the processing does the work. The University of Georgia’s orange marmalade even gives two times: 5 minutes in sterilised jars or 10 minutes in clean, hot ones. NCHFP adds that sterile jars are preferred for low-pectin fruits, because the extra 5 minutes may weaken the gel. ## Lids, dishwashers and the open-pan question Use a new flat lid on every canning jar; the screw bands can be reused if they aren’t rusty, dented or bent. Prepare lids exactly as their maker directs. A dishwasher is fine for washing jars, but NCHFP is clear that washing doesn’t sterilise them, and that processing filled jars in a dishwasher, oven or microwave isn’t recommended. That points to the real difference between the two columns. British open-pan jam is potted hot into hot, sterilised jars and sealed, with no further heating. USDA and NCHFP do not recommend this open-kettle approach, because it does not prevent all risks of spoilage; their tested recipes process the filled jars. Whichever you follow, store jars somewhere cool and dark, refrigerate after opening, and throw away any jar that grows mould. ## What to put on a gift label Edible Christmas gifts are lovely; just make sure the label says what someone needs to know. Put the name, the date it was made, and how to store it. For jars processed in a canner, NCHFP’s advice is a cool, dark, dry place at 50 to 70 °F (10 to 21 °C), best within a year, and in the fridge once opened, where regular jam is best used within a month. Reduced-sugar jams lose quality sooner (within 6 to 8 months), refrigerator spreads are used within 4 weeks, and freezer jam keeps up to a year frozen but about 3 weeks in the fridge. Listing the ingredients helps anyone avoiding a food. Printable jar-label packs and preserving e-books are often emailed after a sign-up form. A [CleanTempMail temporary inbox](https://cleantempmail.com/) needs no sign-up and empties itself after three days, so it takes the download link without the newsletters that follow. Download the file straight away, and use your real address for orders and anything you may need later. ## Selling your jam Selling is regulated, and this is general information, not legal advice. In England, Wales and Northern Ireland, the Food Standards Agency says a new food business, including one run from home, must register with its local authority at least 28 days before trading; registration is free. Anything sold as jam must also meet composition and labelling rules: England has The Jam and Similar Products (England) Regulations 2003, and Scotland, Wales and Northern Ireland each have their own. Your council’s environmental health team can say what applies to you. In the US, cottage food laws are set state by state and vary widely: what you may sell, where, and what the label must say. The National Agricultural Law Center keeps a compilation of every state’s cottage food statutes (updated April 2025); check your state’s department of agriculture or health before your first market. ## Worked examples - **A batch that makes 4 half-pints:** 5 half-pint jars with one spare, 5 new flat lids and 5 bands. - **2 litres of jam into 300 ml jars:** 6 full jars and a part-jar, so 7, or 8 with a spare. - **Sterilising at 3,200 ft (975 m):** 10 minutes plus 3, so boil the empty jars 13 minutes. For the processing time after filling, use the [canning time calculator](https://jellyglimmer.me/water-bath-canning-time/); for the batch itself, the [jam calculator](https://jellyglimmer.me/). Bringing jars to a party? [Kindred Picnic](https://kindredpicnic.cyou/) works out food quantities for the rest of the spread. ## Questions **How do you sterilise jam jars in the oven?** Wash the jars and lids in hot, soapy water, rinse, then dry them on a tray in an oven at 140 °C (120 °C fan, gas 1) for about 10 to 20 minutes. Boil rubber seals instead of baking them. Fill the jars while they are still hot. **Do you need to sterilize jars for water bath canning?** Only if the processing time is under 10 minutes, which covers most jams and jellies at sea level. Boil the empty jars for 10 minutes, plus 1 minute per 1,000 ft. For 10 minutes or more, clean hot jars are enough. **Does a dishwasher sterilise jars?** NCHFP says washing jars by hand or in a dishwasher cleans them but does not sterilise them. Boil them if your recipe needs sterile jars. **Can I reuse canning lids?** Not the flat lids: use a new one on each jar. Screw bands and Mason jars can be reused many times if they are in good condition. **What should a homemade jam label say?** The name, the date it was made and how to store it, such as: store in a cool, dark, dry place, best within a year, refrigerate after opening. Add the ingredients so anyone avoiding a food can check. ## Sources - US sterilising rule and method: [NCHFP, Sterilization of Empty Jars](https://nchfp.uga.edu/how/can/general-information/sterilization-of-empty-jars/) (USDA Complete Guide to Home Canning, 2015; page reviewed 2 February 2017). Washing, lids and bands: [NCHFP, Recommended Jars and Lids](https://nchfp.uga.edu/how/can/general-information/recommended-jars-and-lids/). Sterile jars and weak gels: [NCHFP, General Information on Canning Jams, Jellies, and Marmalades](https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/general-information-on-canning-jams-jellies-and-marmalades/). - Methods not recommended: [NCHFP, Equipment and Methods Not Recommended](https://nchfp.uga.edu/how/can/general-information/equipment-and-methods-not-recommended/). Orange marmalade jar options: [NCHFP, Orange Marmalade](https://nchfp.uga.edu/how/make-jam-jelly/marmalades/orange-marmalade/) (UGA, April 2018). - UK oven method: [BBC Good Food, How to sterilise jars for jams and preserves](https://www.bbcgoodfood.com/howto/guide/how-sterilise-jars) (3 June 2026) and [BBC Food, How to sterilise jars](https://www.bbc.co.uk/food/how_to_cook/watch/how_to_sterilise_jars) (last updated 11 November 2024). - Storage and label wording: [NCHFP, Storing Home-Canned Jams and Jellies](https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/storing-home-canned-jams-and-jellies/), [Stiff Jams or Jellies](https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/stiff-jams-or-jellies/) (reduced-sugar quality) and [Making Reduced-Sugar Fruit Spreads](https://nchfp.uga.edu/how/make-jam-jelly/reduced-sugar-recipes/making-reduced-sugar-fruit-spreads/). - UK registration: [Food Standards Agency, Starting a food business](https://www.gov.uk/guidance/starting-a-food-business) (GOV.UK, last updated 19 August 2026). Jam rules: [The Jam and Similar Products (England) Regulations 2003](https://www.legislation.gov.uk/uksi/2003/3120/contents), with Scotland’s (2004), Wales’s (2018) and Northern Ireland’s (2018) on [legislation.gov.uk](https://www.legislation.gov.uk/) (checked 5 November 2026). - US cottage food laws: [National Agricultural Law Center, “Cottage Food” Laws](https://nationalaglawcenter.org/state-compilations/cottagefood/) (updated April 2025).